The Navy is still investigating four accidents involving ships in the Pacific this year - accidents that led to the deaths of 17 sailors and untold millions of dollars in repairs. So what happened? Some naval experts are pointing to overworked crews and to the stress of frequent deployments because of too few ships. But as NPR's Tom Bowman reports, others point to a simpler reason - lack of training.

TOM BOWMAN, BYLINE: When Bryan McGrath left college as a Navy ensign back in 1987, he spent more than a year learning how to drive a warship. There were classes, simulators, time in the water steering a patrol craft. Then he was off to the fleet.

BRYAN MCGRATH: So I showed up at that ship with a unbelievable amount of education about the basics of what my ship was doing - how to navigate it, how to maintain it, how to operate it.

BOWMAN: Fast forward two decades - McGrath is in command of a ship. And the new ensigns coming aboard - no more months of classes. They've been given a load of CDs. That's right - online learning. McGrath was stunned how their skills compared to what was expected when he first went to sea.

MCGRATH: It was night and day. They did not have a well-developed sense of what the job and what the blocking and tackling skills of a surface warrior were.

BOWMAN: It was 2003 when the Navy issued those CDs to junior officers. McGrath and other retired officers say the Navy was trying to save money by doing away with months of classes and making sure crews quickly got to their ships. It borrowed those efficiencies from the business world.

KEVIN EYER: Driving a ship is the fundamental bread-and-butter thing that we do.

BOWMAN: Kevin Eyer is a retired Navy captain who commanded three ships.

EYER: They give you 21 computer disks and say, go to your ship, and you'll learn all this there while you're in your first job.

BOWMAN: That was a problem because the more seasoned officers often didn't have time to teach those ensigns the basics, says retired Vice Admiral Peter Daly.

PETER DALY: This presumption that the ships can make up for people who are untrained and just do it on the job is flawed.

BOWMAN: So in 2010, just seven years after the CDs were issued, the commander of the Atlantic Fleet, Admiral John Harvey, went to Congress to tell lawmakers it was all a mistake.

JOHN HARVEY: I expressed the sentiment that was a experiment that did not pan out in a real world.

BOWMAN: The Navy increased the classroom time and more time on simulators, but not as much time as they had in the 1970s, which brings us to the present and the recent mishaps, which some officers say are the direct result of those earlier training decisions. Again, retired Navy Captain Kevin Eyer...

EYER: The root cause - primary root cause is training. It will take years to fix the problem.

BOWMAN: The Navy isn't ready to say whether a lack of training was a primary cause or played a part in the recent accidents. But the Navy's top officer, Admiral John Richardson, says basic skills will be part of the widespread investigation.

JOHN RICHARDSON: It'll also include a review of how we train and certify our surface warfare community, including tactical and navigational proficiency.

BOWMAN: Tactical and navigational proficiency - basically, how to steer a ship, and understand where you are and where you're going. So how did the Navy come to this with a top admiral having to review whether his officers can even handle a ship? Retired Admiral Harvey agrees it comes down to training.

HARVEY: These fundamentals have not changed since Noah took the ark to sea.

BOWMAN: And the Navy, he says, has more to do to improve the effectiveness of training and the basics of driving a ship. Tom Bowman, NPR News, Washington.